Report on the Global HIV/AIDS epidemic

Waking up to devastation
There is no phenomenon apart from the AIDS epidemic that could possibly explain this
recent drastic rise in mortality after years of declining death rates. Indeed, smaller community-based studies with information on the cause of death show that in countries
where just under 10% of the adult population has HIV infection, almost 80% of all
deaths in young adults aged 25-45 are associated with HIV. The proportion of HIVrelated deaths is likely to be even higher in areas with higher HIV prevalence rates.
In some countries, over a third of 15-year-olds may die of AIDS
High and stable HIV prevalence rates are bad news. But there is worse news.
Prevalence rates do not reflect the true impact of the epidemic. The 15-49-year-old
age group includes people who are not yet infected with HIV but who will be one day.
And it excludes men and women born 15-49 years ago who were infected with HIV
but have already died. If the probability that a person will become infected at any time
in his or her life is summed up, the cumulative figure is higher than the "snapshot" provided by current prevalence rates.
To give a better idea of the actual risk of dying of HIV-associated disease, researchers
have built models to follow people throughout their lives, examining their exposure to
risks of infection with HIV at each age. The risks are calculated from patterns of HIV
infection at each age observed in African communities. In general, the rate of new
infections peaks among women in their early 20s and among men slightly later, and
tapers off at older ages. The rate of new infections at each age is determined by the
current phase of the HIV epidemic in a country. In the model, men and women also
face the competing risk of dying of other causes at rates similar to those recorded
before the HIV epidemic.
The results of this exercise are illustrated in Figure 10 for men. Along the bottom of the
graph is the current prevalence of HIV in adults aged 15-49. The vertical axis shows
the probability that a boy who is now 15 years old will die of AIDS. Clearly, the likelihood that a boy now aged 15 will eventually die of AIDS is much higher than the likelihood that a man now aged 15-49 is currently infected with HIV. This sobering fact
remains true even if the rates of new infection fall in the future. The grey line shows the
relationship between current prevalence and the risk of a 15-year-old eventually dying
of AIDS if infection rates stay at current levels - a pessimistic scenario. The red line
shows the relationship if the risk for new HIV infection at each age drops by half over
the next 15 years - in other words, if prevention campaigns are very successful. Even
in this optimistic scenario, however, the proportion of young people who will die of
AIDS is appallingly high in many countries: in virtually any country where 15% or more
of all adults are currently infected with HIV, at least 35% of boys now aged 15 will die
of AIDS.
In countries where HIV infection is concentrated in specific sub-populations - for
example, men who have sex with men - there is a similar relationship between current
HIV prevalence in that group and the lifetime risk of dying of HIV-related disease.

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